The invention relates to a roller-supported pressure roll for textile machines, in particular for texturing machines, having an elastic covering that is slipped over an outer ring.
Such roller-supported pressure rolls with an elastic covering for transporting or pulling a yarn in textile machines are already known. The rolls clamp the yarn between a feeder and the rubber covering. If the yarn is to be transported without problems, the rubber covering must be pressed uniformly against the feeder. To assure that the covering is always aligned parallel with the feeder, the bearing of the covering has to have a degree of freedom. This degree of freedom must be relatively great, so that the allowable tolerances in the machine frame between the fastening of the feeder and the fastening of the pivot lever will not become too close. It has therefore been proposed, in German patent disclosure DE 17 60 142 A1, that the pressure rolls be supported in free-floating fashion, so that they can swing back and forth in the plane defined by their axis of rotation and the shaft of the feeder cylinder of the feeder. To that end, the rotary shaft of the pressure roll is secured to a pivotable shaft. This embodiment is relatively expensive, however, because the structural group requires assembly and must installed in a highly precise orientation on the machine. German patent disclosure DE 29 23 871 proposes a pressure roll that is suspended in pendulum fashion from a bolt oriented transversely to the axis of the roll. This embodiment, too, is relatively expensive. Furthermore, the pressure rolls of the prior art cannot be released from the machine, to allow the elastic covering to be reground, without using tools. This regrinding has to be done several times a year, because of wear of the elastic covering. The pressure rolls of the prior art must either be ground along with the shaft, or else the shaft has to be removed in a separate step before the grinding is done.
The object of the present invention is to propose a pressure roll which is simple in design and can be removed quickly from the machine without using a tool.
With a pressure roll of the type defined at the outset, this object is attained in that the outer ring is secured by positive engagement to the shaft of the pressure roll by means of a quick-release closure that can be undone without using tools. If the covering of the pressure roll has to be reground, it is now possible in a simple way for only the outer ring and the covering to be removed from the shaft and then ground. The outer ring can be clamped directly into the appropriate grinding machine. It is unnecessary to remove the shaft separately. The provision of a quick-release closure also makes the design and installation of the pressure roll simple, because separate fastening means can be dispensed with. The quick-release closure can for instance be formed by a detent connection. It is possible for instance to retain the outer ring by means of an outer cap, which can be snapped into the shaft or into a roller bearing receiving ring of the shaft and which thereby holds the outer ring firmly on the shaft. The quick-release closure can, however, also be a bayonet or screw closure.
Further advantages are attained if the shaft of the pressure roll is embodied in ball-like fashion. Then no separate pivot shaft for suspending the pressure roll in pendulum fashion is needed. By replacing the cylindrical shaft with a shaft embodied in ball-like fashion, there is also less pressure on the pivot bearing per unit of surface area. This version also requires fewer parts and is thus more economical.
A preferred exemplary embodiment of a pressure roll of the invention is described in further detail below, in conjunction with the drawing.